Process of working with hydrogen under pressure.



' Pressure, of which UNITED sirAtrEs PATENT orrioa.-

CARL BOSCH, 0F LUDWIGSHAFEN-ON-THE-RHINE, GERMANY, ASSIGNOR TO BADISCHE I l ANILIN & SODA'FABRIK, OF LUDWIGSHAEEN-ON-THE-BHINE, GERMANY, A 136R- PORATION.

PROCESS 0]! WORKING WITH HYDROGEN UNDER PRESSURE.

No Drawing. Y

To all whom it may concern Be it known that I, CARL BosoH, citizen of the German Empire, residing at Ludwigshafen on the Rhine, Germany, have in: vented new and useful Improvements in the Process of Working with Hydrogen Under the following is a specification.

In operations in which hydrogen is em ployed under pressure in iron tubes or vessels at high temperatures, if the mechanical solidity of the iron is due to the presence of carbon, the tubes or vessels suffer to such an extent that, after a very short time, they are not able to withstand the high pressure em- Eployed. I have found that this is due to the action of, the hydrogen, ion the carbon in such a manner that the carbon is converted into gaseous compounds and thus removed from the iron. In the specification of application for patent Serial No. 691,731, I have stated that the disadvantage can be overs come by taking care that the wall which has to sustain the pressure is maintained at a temperature not essentially exceeding 40 C. and in that case any sort of, iron which possesses the requisite mechanical solidity can be employed, whether such iron contains much or little carbon or is free from carbon. In continuing my researches inthis direction I have now discovered that operations in which hydrogen is employed under pressures exceeding, say, five atmospheres and at high temperatures, can be carried .out' when the walls of the. tubes or vessels which are supporting the pressure possess a temperature essentially above 450 walls be made of iron in which the requisite mechanical solidity of the metal is secured by alloying therewith a metallic solidity giving element such as chromium, vanadium, tungsten, molybdenum, and the like. In these cases it is indifferent whether the iron employed containscarbon or not, since .even if the iron originally contained carbon Specification of Letters Patent.

0., provided the said gen at a raised temperature and at a pres Patented Feb. 3, 1914.

Application filed June 5, 1913. Serial No. 771,898.

. the high temperature and pressure employed causes the removal of the carbon from the iron, the remaining alloy of the iron and element as aforesaid still possesses 'sufiicient mechanical solidity to prevent the tube or, vessel from giving way under the conditions obtaining.

-As instances of alloys which are suitable for use according to my invention, I mention steel containing 18% of tungsten and 3% of chromium, and steel containin 2.9% of chromium and 0.2% of carbon. prefer to avoid the use of alloys containing too high a percentage of nickel.

The present invention is of great value when preparing ammonia synthetically from nitrogen and hydrogen with the aid of catalytic agents. Now what I claim is 1..The process of working with hydro-. gen at a raised temperature and at a pressure exceeding five atmospheres, which corf:

sists in passing the hydrogen under pressure through an iron tube or vessel the walls ofwhich are maintainedat a temperature essentially above 450 C. and contain a metallic solidity giving element.

'2. The process of working with hydrogen at' a'raised temperature and at apressureexceeding five atmospheres, which consists in passing the hydrogen under pressure.

through an iron tube or vessel the walls of which are maintained at a temperature es-,

sentially above 450 C. and contain a metallic solidity givingrelement, but are practically free from'c'a-rbon.

3. The process of working with hydrosure exceeding five atmospheres,'which consists in passing the hydrogen under pressure through an iron tube or vessel the Walls of which are maintained at'a temperature es: sent-ially above 450 C. and contain chromiumI I l 4. The process of working with hydrogen at a raised temperature and at ap'ressure'exceeding 'five atmospheres, which consi'sts in passing the hydrogen under pressure my hand in the presence of two subscribing through an iron tube or vessel the Walls of witnesses.,

which are maintained at a temperature es- CARL BOSCH. sentially above 450 C. end contain chro- Witnesses: 5 mium, but are practically .free from carbon. J ALEc. LLOYD,

-In testimony whereof I have hereunto set JOSEPH PFEIFFER. 

